Synthesis of Allylic and Propargylic Trifluoromethyl Thioethers by Copper(I)-Catalyzed Trifluoromethylthiolation of Allylic Bromides and Propargylic Chlorides
copper(I)-catalyzed trifluoromethylthiolation of allylicbromides by using elemental sulfur and CF3SiMe3. This rate of this transformation was significantly accelerated in the presence of 18-crown-6, and the reaction afforded the desired products in moderate to excellent yields with high stereo- and regioselectivity. This method can tolerate a number of functional groups and provides facile access to a variety
Copper(I)-Catalyzed Regio- and Chemoselective Single and Double Addition of Nucleophilic Silicon to Propargylic Chlorides and Phosphates
作者:Chinmoy K. Hazra、Martin Oestreich
DOI:10.1021/ol301827t
日期:2012.8.3
Copper(I)-catalyzed propargylic substitution of linear precursors with (Me2PhSi)2Zn predominantly yields the γ isomer independent of the propargylic leaving group. The thus formed allenylic silane reacts regioselectively with another equivalent of (Me2PhSi)2Zn, yielding a bifunctional building block with allylic and vinylic silicon groups. The reaction rates of both steps are well-balanced for chloride
Hot couple: Propargyl azides were coupled with carboxylic acids by an iron‐catalyzed dehydrogenativeCObondformation (see scheme). This method enables propargylicCHfunctionalization under mild reaction conditions and also may involve the application of the azido moiety as an assisting group in CH activation.
An efficient enantioselective alkylation of N‐unprotected 3‐substitutedoxindoles was realized by using a chiral N,N′‐dioxide/scandium(III) complex as the catalyst. A wide range of 3,3‐dialkyl substitutedoxindoles with quaternary stereocenters were obtained in high yields and ee values (up to 98% yield and 99% ee).
Synthesis of propargylic and allylic trifluoromethyl selenoethers by copper-mediated trifluoromethylselenolation of propargylic chlorides and allylic bromides
The copper-mediated trifluoromethylselenolation of propargylic chlorides and allylic bromides is described. This approach provides a wide range of propargylic and allylic trifluoromethyl selenoethers in moderate to good yields. These results open the way to synthesis strategies for various trifluoromethylselenolated compounds.